# 🎠 Round float to any precision in Go

introduction numbers math

To round a floating-point number in Go, you can use the `math.Round()` function from the built-in `math` package. However, this function rounds to the nearest integer, so it cannot be used directly to round a float to a particular precision. But you can use it to create your own function that rounds to any decimal places. All you need to do is:

1. multiply the number to be rounded times 10 to the power of `X`, where `X` is the precision you want to achieve
2. round this raised number to the nearest integer value using the `math.Round()` function
3. divide the rounded number by 10 to the power of `X`, where `X` is the rounding decimal precision

In this way, by rounding the raised number to the nearest integer and then dividing, we get a number rounded to the specified decimal places.

## Examples

The `roundFloat()` is a floating-point rounding function, working as described above. The way it works is shown in the example:

``````package main

import (
"fmt"
"math"
)

func roundFloat(val float64, precision uint) float64 {
ratio := math.Pow(10, float64(precision))
return math.Round(val*ratio) / ratio
}

func main() {
number := 12.3456789

fmt.Println(roundFloat(number, 2))
fmt.Println(roundFloat(number, 3))
fmt.Println(roundFloat(number, 4))
fmt.Println(roundFloat(number, 5))

number = -12.3456789
fmt.Println(roundFloat(number, 0))
fmt.Println(roundFloat(number, 1))
fmt.Println(roundFloat(number, 10))
}
``````

Output:

``````12.35
12.346
12.3457
12.34568
-12
-12.3
-12.3456789
``````

### Round float to 2 decimal places

Full example of rounding a float to 2 decimal places:

``````package main

import (
"fmt"
"math"
)

func roundFloat(val float64, precision uint) float64 {
ratio := math.Pow(10, float64(precision))
return math.Round(val*ratio) / ratio
}

func main() {
number := 12.3456789
fmt.Println(roundFloat(number, 2))
}
``````

Output:

``````12.35
``````

### Round float to 3 decimal places

Full example of rounding a float to 3 decimal places:

``````package main

import (
"fmt"
"math"
)

func roundFloat(val float64, precision uint) float64 {
ratio := math.Pow(10, float64(precision))
return math.Round(val*ratio) / ratio
}

func main() {
number := 12.3456789
fmt.Println(roundFloat(number, 3))
}
``````

Output:

``````12.346
``````

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